The present invention generally relates to routers and, more specifically, to virtual routers in a split plane architecture.
A physical router typically includes a number of physical interfaces that are coupled respectively to corresponding packet sources. Packets received from the packet sources are received via the physical interfaces and forwarded by the physical router to their intended destinations.
A virtual router is generally defined as a collection of threads, either static or dynamic, in a routing device that provides routing and forwarding services similar to those offered by physical routers. A virtual router need not be a separate operating system process. The virtual router simply has to provide the perception or illusion that a dedicated router is available to satisfy the needs of the network(s) to which it is connected. A virtual router, like its physical counterpart, is an element in a routing domain which may include other routers that are either physical or virtual.
Virtual routers are used to implement Layer-3 virtual private networks (VPNs). A VPN is defined as one or more wide area network (WAN) links over a shared public network, typically over the Internet or an IP (Internet Protocol) backbone from a network service provider that simulates the behavior of dedicated WAN links over leased lines. Virtual routers support VPNs at Layer-3 of the Open Systems Interconnections (OSI) internetworking model. Network links that constitute network ports, VLANs (virtual local area networks) or virtual circuits are partitioned amongst the virtual routers. The virtual routers then perform routing on the individual links that are bound to them thus achieving network separation.
A router generally comprises a routing element and a forwarding element. To implement virtual routing, the routing and forwarding elements have to be distinctly separate. There are multiple ways of achieving this separation.